Steam generator



Aug. 14, 1945. G SANDERS 2,382,176 I STEAM GENERATOR Filed June '15, 1942 b eaz e Sazzdez s Patented Aug. 14, 1945 OFFICE STEAM GENERATOR George Sanders, Larne Harbour, Northern Ireland Application June 15, 1942, Serial No. 447,120

In Great Britain June 23, 1941 2 Claims.

This invention relates to an improved steam generator for the generation of steam at medium and high pressures.

In the arrangement according to the present invention the steam is generated in two stages,

viz., low and high pressure respectively, the working pressure being a resultant of these two pressures. The high pressure live steam is used as it leaves the high pressure stage to draw live steam from the low pressure stage and compress it to considerably higher working pressure.

The advantages of the arrangement according to the invention are as follows: the drums are subjected to low pressures only so that they are cheap to construct; the stability of the drum type of boiler is combined with the quick steaming qualities of the boiler of the flash type; and the invention can be applied to existing low pressure boilers enabling them to meet modern steam con ditions.

According to one arrangement, a water tube boiler of any known type is used for the first stage to generate steam at a low pressure, say up to 200 lbs. per square inch, while the high pressure stage, more particularly of tubular design, is preferably constituted by a monotube boiler, generating high pressure superheated steam, say at a pressure of over 1000 lbs. per square inch. The high pressure stage may be accommodated in the combustion chamber of the low pressure stage, in such a manner as to form water walls therein, being more particularly arranged round the walls thereof, or the high pressure unit may be separately fired. i

Water is taken from one of the drums of the low pressure boiler by means of an auxiliary feed pump and forced through the high pressure may then, if required, be passed through a superheater in the usual way.

The steam for operating the feed pumps may be taken at either high or working pressure and be exhausted into the low pressure steam drum.

The accompanying drawing illustrates by way of example one mode of carrying the invention into effect.

a is a. water tube boiler in which low pressure steam is generated. By means of a pump b water is drawn from the drum 0 of the boiler and forced past a non-return valve 11 to a monotube boiler e arranged round the walls of the combustion chamber 1 and in which high pressure superheated. steam is generated. By means of an ejector g operated by the high pressure steam coming from the monotube boiler low pressure steam is drawn past a non-return valve h from the drum 0 of the boiler and forced into the working steam range at a pressure considerably higher than in the drum 0. I

The details of construction may be varied without departing from the scope of the invensteam, a monotube boiler for the generation of high pressure superheated steam, a pump for drawing water from the said low stage water tube boiler and for forcing it into the said high stage monotube boiler, an ejector arranged at the outlet of the said mono-tube high Pressure steam boiler for the passage of the high pressure superheated steam coming from the said monotube boiler and for drawing low pressure steam from the said 10W stage water tube boiler and nonreturn valves arranged between the pump and the monotube boiler and between the ejector and the low stage water tube boiler.

2. A steam generating plant comprising a boiler for the generation of low pressure steam, a boiler for the generation of high pressure superheated steam, a pump for drawing water from the said low stage boiler and for forcing it into the said high stage boiler, an ejector arranged at the outlet of the high pressure boiler for the passage of the high pressure superheated steam coming therefrom and for drawing low pressure live steam from the said low stage boiler and a non-return valve arranged between the pump and the high pressure steam boiler.

GEORGE SANDERS. 

